Justyn W. Regini

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The refractive power of a lens is determined largely by its surface curvatures and the refractive index of its medium. These properties can also be used to control the sharpness of focus and hence the image quality. One of the most effective ways of doing this is with a gradient index. Eye lenses of all species, thus far, measured, are gradient index (GRIN)(More)
Whole eye lens and alpha-crystallin gels and solutions were investigated using X-ray scattering techniques at temperatures ranging from 20 degrees C to 70 degrees C. In whole lens isolated in phosphate-buffered saline, the spacing of the dominant X-ray reflection seen with low-angle scattering was constant from 20 degrees C to 45 degrees C but increased at(More)
The lens, a major optical component of the eye, has a gradient refractive index, which is required to provide sufficient refractive power and image quality. The refractive index variations across the lens are dependent on the distributions and concentrations of the varying protein classes. In this study, we present the first measurements of the refractive(More)
PURPOSE The purpose of this study is to compare the structural integrity of bovine lenses using small-angle X-ray diffraction techniques, before and after freezing, using both liquid nitrogen and a -20 degrees C freezer to understand the molecular changes that occur and to see if any permanent structural changes result from the freezing and thawing process.(More)
PURPOSE Alpha-crystallin, a ubiquitous molecular chaperone, is found in high concentrations in the lens. Its structure and precise mechanism of action, however, are unknown. The purpose of these experiments was to further the understanding of the chaperone function of alpha-crystallin. METHODS X-ray- and neutron-solution-scattering studies were used to(More)
The structural basis of zones of discontinuity in the living human eye lens has not been elucidated, and there is no conclusive explanation for what relevance they may have to the structure and function of the lens. Newly developed synchrotron radiation based X-ray Talbot interferometry has enabled the detection of subtle fluctuations in the human eye lens(More)
The fixed stromal charge of bovine corneas, osmotically clamped at physiological hydration, was altered by regulating the amount of chloride ions bound to the matrix. We measured the local fibrillar collagen order using X-ray diffraction methods. As the bound anions increased up to physiological values, the local fibrillar order increased to an optimal(More)
De-epithelialised and de-endothelialised bovine corneal stromas with a hydration of 3.2 equilibrated at 154 mM NaCl and buffered at pH 7.4 had their optical density (400-750 nm) measured. Stromas equilibrated against 10, 20, 30, 50 or 100 mM NaCl made isotonic to 154 mM NaCl by supplementing with sorbitol were progressively more transparent as NaCl(More)
PURPOSE The molecular chaperone αB-crystallin is found in high concentrations in the lens and is present in all major body tissues. Its structure and the mechanism by which it protects its target protein from aggregating and precipitating are not known. METHODS Dynamic light scattering and X-ray solution scattering techniques were used to investigate(More)
alpha-Crystallin, one of the main constituent proteins in the crystalline lens, is an important molecular chaperone both within and outside the lens. Presently, the structural relationship between alpha-crystallin and its target proteins during chaperone action is poorly understood. It has been hypothesised that target proteins bind within a central cavity.(More)